1. Field of the Invention
The present invention pertains to liquid crystal display (LCD) drivers, and in particular pertains to a signal processing system which will drive large active matrix LCD displays at high speeds without sacrificing quiescent current as in known amplifier configurations used to drive an active matrix LCD display.
2. Description of the Prior Art
Military and commercial applications for flat panel, active matrix LCD's are growing. There is a need for "next generation" IC's which can take full advantage of the capabilities of current and upcoming active matrix displays by providing extreme image accuracy with a large number of gray levels. Space is a primary concern in applications using flat panel displays.
Active matrix displays can provide advantages over conventional LCD's in the areas of viewing angle, response time and information content. Military and commercial applications such as cockpit displays, mapping displays and imaging systems can utilize these features to create extremely accurate image reproductions. A new generation of complex mixed signal driver chips are required to implement these systems.
Current system architectures for LCD drivers employ both row and column driver IC's. The column driver is a high speed chip having responsibility for accurate generation of the gray shade voltage levels. These IC's need to be fast, handle large voltages, have a multitude of outputs, provide low offset error, contain tens of thousands of transistors, and yet minimize power. These conflicting design issues require careful analysis in the light of current IC technology.
In previous active matrix driver chips, power consumption was not an issue due to the relatively slow speed of the chips and the low number of gray scales provided. In a 256 gray level display however, both quiescent power consumption and speed are critical electrical issues affecting system performance. Thus, there exists a need in the art for an active matrix driver chip which is capable of driving large resistive/capacitance loads in a very short time period while simultaneously holding a particular voltage with extreme accuracy and without sacrificing quiescent current.